The present invention relates to a clamping device for various objects and, in particular, to a cable tie for constraining plural objects.
A number of fastening or clamping devices have been devised for a variety of purposes. For example, clamps are used with electrical systems to connect electric shielding or insulation about electric wires, especially about electrical connectors that receive current carrying conductors. Clamps used in such applications are typically referred to as cable ties.
Cable ties generally are of one-piece construction, consisting of a metal or plastic band with a buckle or head attached rigidly to one end of the band. The free end of the band feeds through the buckle to form a loop enclosing the electrical wires. The buckle typically contains locking teeth or tabs which interlock with slots or teeth in the band during band adjustment to retain a desired periphery of the band.
Disadvantages associated with prior cable ties result from the bulky, irregularly contained buckles typically used. Such buckles, in addition to being aesthetically displeasing, frequently inflict damage or injury when inadvertently contacted by objects or persons.
The object of this invention, therefore, is to provide a cable tie with an improved low profile and smoothly contoured head.
The invention is a latchable tie for tying together plural objects and including a flexible strap with an elongated section defining a longitudinal axis and having a substantially uniform transverse width, a head end, a tail end, an upper surface and a lower surface; the lower surface defining a plurality of longitudinally spaced apart first teeth extending transversely to the axis; and a head defining an outer end portion, an inner end portion joined to the strap, an outer opening in the outer end portion, an inner opening in the inner end portion, a channel extending between the outer opening and the inner opening and adapted to receive the tail end of the strap, a bottom surface for contacting a portion of the objects being tied, an upwardly opening cavity disposed between the inner opening and the strap, and a cavity opening in the bottom surface and communicating vertically with the cavity; and the cavity and cavity opening each having a transverse width greater than the uniform transverse width of the strap. Also included is a latch mechanism disposed in the channel and defining upwardly projecting longitudinally spaced span second teeth for engaging the first teeth. After insertion of the tail end of the strap through the channel in the head and severing an excess portion of the tail end, the cavity and cavity opening retain a remaining portion of the tail end.
According to one feature of the invention, the strap further includes a transition section joining the elongated section and the inner end portion of the head, the cavity and cavity opening are straddled by transversely spaced apart connection portions of the head, the connector portions extend between the inner opening and the transition section, and the transition section defines an inclined ramp surface partially defining the cavity and sloping upwardly from the cavity opening toward the strap. The ramp surface upwardly directs the tail end of the strap to facilitate severing thereof.
According to another feature of the invention, the elongated section has a uniform transverse cross-sectional area, and the connecting portions together define between the inner opening and an inner end of the cavity opening a combined minimum aligned transverse cross-sectional area substantially equal to or larger than the uniform cross-sectional area. The minimum cross-sectional area prevents the existence of a rupturable weak point in the strap.
According to an additional feature of the invention, the connector portions are tapered downwardly from the inner opening to the transition section. The tapered connector portions desirably enhance the flexibility of the head.
According to further features of the invention, the transition section has transverse cross-sectional areas diminishing between the head and the elongated section, and also defines transversely spaced apart side surfaces and upper and lower connecting surface portions extending therebetween with at least one of the connecting surface portions defining transverse recesses. The transition section provides a structurally sound connection between the head and strap and the recesses facilitate bending of the transition section to accommodate the curvature of a bundle being secured.
According to still other features of the invention, the head further defines a bottom opening in the bottom surface and communicating with the channel; and the latch consists of a pawl defining the second teeth, one end portion disposed in the bottom opening and projecting below the bottom surface, and an opposite end portion movably joined to the head so as to allow movement of said one end portion into the channel. In response to forces produced by contact of the one end portion with a portion of the objects being tied, the second teeth on the pawl are forced into tighter engagement with the first teeth on the strap.
According to yet another feature of the invention, the tie includes a guide joined to the outer end portion and defining an uncovered, guide surface aligned with the longitudinal axis and terminating at the outer opening; the guide surface having a length l at least xc2xc a length L of the channel. The guide surface is arranged to guide the tail end of the strap through the outer opening during use of the tie.
According to another feature of the invention, the guide also includes wall portions straddling the guide surface and having inner surfaces joined to the guide surface by concave joint portions. The wall portions further facilitate insertion of the strap into the head and the joint portions enhance the structural strength of the guide to prevent rupture thereof.